JPH10286614A - Method for controlling width in continuous hot rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the width with high accuracy in hot finish rolling by preventing delayed response in the longitudinal direction of a material to be rolled. SOLUTION: In a width control method in finish rolling equipment which is provided with a vertical edger 2 on the inlet side of a continuous hot rolling mill group 1 consisting of plural rolling stand train, by measuring the width of the material 7 to be rolled between a 1st stand 1-1 and a 2nd stand 1-2 of the continuous hot rolling mill group 1, calculating deviation of the measured width from the preset target value of the width on the outlet side of the 1st stand based on a rolling schedule and correcting the amount of edging of the vertical edger 2 based on the deviation, quick response and highly accurate width control are enabled and yield is improved by reduction of inferior quality of products and decrease of the amount of trimming.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a sheet width in a finishing mill having a vertical edger on the entrance side of a group of continuous hot rolling mills.

[0002]

2. Description of the Related Art A hot continuous rolling mill generally includes a group of rough rolling mills each having a plurality of rolling stands and a group of finishing rolling mills. And then finished into a hot-rolled steel strip of a predetermined size by a group of finishing mills. Normal,
In the hot-rolled steel strip obtained in this manner, a sheet width variation (sheet width deviation) of about several mm to several tens mm occurs, and the yield is remarkably reduced due to poor product quality or trimming by a side trimmer. There were drawbacks such as.

[0003] The sheet width fluctuations are roughly classified into those caused by a group of rough rolling mills and those caused by a group of finishing rolling mills.
Significantly impact product quality. In other words, although it is necessary to perform rolling so as to have a predetermined sheet width also by the rough rolling mill group, even if controlled to a predetermined sheet width by the rough rolling mill group,
Unless the width control of the finishing rolling mill group is reliably performed, the control of the rough rolling mill group becomes meaningless.

[0004] The causes of the plate width fluctuation of the finishing mill group include temperature variations due to skid marks or variations in the transit time between the stands in the longitudinal direction of the material to be rolled, in other words, between the stands. There are variations in the tension applied to the material to be rolled and the time during which the tension is applied. However, no matter what the cause, the width variation of the exit side of the hot finishing mill may be smaller than the width required for the product in the narrow portion. There is a drawback that the target plate width must be set large in anticipation, and the amount of trimming at the finishing stage of the product becomes large, thereby significantly lowering the yield.

[0005] As a method of controlling the exit side sheet width of the hot finishing mill, a method of controlling the sheet width to be constant by controlling the tension of the material to be rolled, a vertical edger is used, and the opening is adjusted. A method of controlling the plate width of the material to be rolled by controlling the tension of the material to be rolled and the opening of a vertical edger arranged between the stands to thereby keep the plate width of the material to be rolled constant Three have been proposed.

[0006] As a method of controlling the sheet width to be constant by controlling the tension of the material to be rolled, for example, a sheet width or a sheet width deviation is detected at the entrance of a rolling mill, and the sheet width or the sheet width deviation is detected. (Japanese Patent Publication No. 58-51769), a method for detecting a sheet width or a sheet width deviation of a material to be rolled between stands of a hot finishing rolling mill, based on the detected value, A method in which the speed of a mill motor of a stand is adjusted to control the tension between the stands of a material to be rolled to control the plate width to be constant (JP-A-60-141319).
Publication).

As a method of controlling the width of the material to be rolled to be constant by using a vertical edger and adjusting the degree of opening, there is a method of controlling the width or width of a strip between stands of a continuous finishing mill. A method of detecting a deviation and controlling the roll width of a vertical edger installed between stands based on the detected value to control the sheet width to a predetermined size (Japanese Patent Laid-Open No. 62-57705); A pair of side rolls in which a plurality of rolls are arranged in the housing along the moving direction of the material to be rolled on the entrance side of the rolling mill is installed, and the width of the material to be rolled on the exit side of the rolling mill is detected, and the detected width of the material is A method of determining the amount of reduction of the material to be rolled on the side rolls based on the side rolls and controlling the side rolls so that the sheet width becomes a set value (Japanese Patent Publication No. 3-78166). Install the edger Measure the temperature distribution in the width direction of the material to be rolled at the edger entry side, measure the width of the material to be rolled at the exit side of the continuous hot rolling mill, and further measure the width of the material to be rolled near the winder. A method has been proposed in which the edger opening is controlled by a predetermined formula based on the above measured values (JP-B-6-18653).

[0008] Further, as a method of controlling the plate width of the material to be rolled to be constant by adjusting the tension of the material to be rolled and the opening of the vertical edger disposed between the stands, there is a method of controlling the width of the material to be rolled in front of a predetermined stand. Detects rolled material temperature and strip width,
Determine the tension applied to the material to be rolled between the predetermined stand based on the detected temperature and the width of the material to be rolled,
At the time when the detected temperature and the width of the material to be rolled reach between the predetermined stands, the tension between the stands is corrected as the determined tension to correct the width of the material to be rolled, and the predetermined width is corrected. Detecting the actual plate width and temperature of the material to be rolled whose plate width has been corrected between the stands, detecting an error of the width correction in the predetermined stand from the detected actual plate width,
A method of adjusting the roll opening of a vertical edger provided between stands after the predetermined stand based on the detected width correction error and temperature (Japanese Patent Laid-Open No. 62-1560).
No. 10) has been proposed.

[0009]

To control the tension of the material to be rolled, Japanese Patent Publication No. 58-51769 and Japanese Patent Application Laid-open No.
The method disclosed in Japanese Patent Application Laid-Open No. 141319 has the following problems in the case where a large width control of a material to be rolled is performed. (1) The change in the sheet width is large due to the influence of temperature variations in the sheet width and sheet thickness direction of the material to be rolled. (2) Control response is slow. (3) Due to the tension fluctuation, the rolling property of the material to be rolled becomes unstable.

[0010] Tokuho 3 to control the opening of the vertical edger
In the method disclosed in Japanese Patent No. 78166/1992, since a vertical edger between stands is used, the thickness of the material to be rolled is as thin as 20 mm or less, and buckling occurs or the sheeting property of the material to be rolled becomes unstable, resulting in horizontal rolling. There is a problem that there is a possibility that narrowing down may occur. 6-186
The method disclosed in Japanese Patent No. 53 is based on the temperature distribution of the material to be rolled on the entrance side of the finishing mill, the measurement result of the width of the sheet on the exit side of the finishing mill, and the width of the sheet just before winding. Therefore, there is a disadvantage that a control delay in the longitudinal direction of the material to be rolled occurs.

The method disclosed in Japanese Patent Application Laid-Open No. 62-156010 for controlling the tension of the material to be rolled and the opening of the vertical edger uses a vertical edger between stands, so that the thickness of the material to be rolled is 20 mm or less. Therefore, there is a problem that buckling may occur or the rolling property of the material to be rolled may be unstable and narrowing may occur in horizontal rolling.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to prevent a response delay in the longitudinal direction of a material to be rolled, to increase a width reduction amount, and to control a sheet width with high accuracy and a high precision. An object of the present invention is to provide a method for controlling a sheet width in continuous rolling during hot rolling.

[0013]

According to the present invention, there is provided a method for controlling a sheet width in hot continuous rolling, comprising the steps of a finishing mill having a vertical edger on the entry side of a continuous hot rolling mill group comprising a plurality of rolling stand rows. In the strip width control method, a strip width of a material to be rolled is measured between a first stand and a second stand of the hot continuous rolling mill group, and the first strip is set in advance based on the measured strip width and a rolling schedule. The deviation from the target plate width on the stand exit side is calculated, and the width reduction of the vertical edger is corrected based on the deviation. In this way, the width of the material to be rolled is measured between the first stand and the second stand of the hot continuous rolling mill group, and the first stand exit side preset based on the measured sheet width and the rolling schedule is set. By calculating the deviation from the target value of the sheet width and correcting the width reduction of the vertical edger based on the deviation, the error in the setup calculation of the width return and width expansion of the dog bone accompanying the width reduction of the vertical edger is reduced. Responsiveness can be corrected quickly. In addition, the width reduction by the vertical edger reduces the width at the entry side of the group of finishing mills where the thickness of the material to be rolled is large. It is possible to control the sheet width of the material to be rolled with high accuracy without causing any reduction in rolling, to reduce defective product quality, and to reduce the amount of side trimming to significantly improve the yield.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The sheet width control of a group of finishing mills according to the present invention can be broadly divided into a setup control and an automatic edger sheet width control. The setup control determines the sheet width W and the surface temperature Tc of the material to be rolled by the sheet width detector and the surface temperature detector of the material to be rolled which are installed on the entrance side of the finishing mill group in order to obtain the sheet width of the final product. To detect. Then, based on the detected sheet width W, surface temperature Tc, and target sheet width Wb at the time of passing the exit side sheet width detector stored in advance for each steel type and product size, the speed and roll opening of each stand of the finishing mill group. And the amount of reduction ΔE of the vertical edger is calculated and controlled. At this time, the target plate width Wa at the time when the plate width detector on the exit side of the first stand passes is also determined.

In this case, assuming that the target sheet width of the steel sheet after finish rolling is Wb, the vertical sheet width of the side of the vertical edger is W, and the width return rate is η, the vertical edger reduction amount to achieve the target sheet width Wb. ΔE is given by equation (1). ΔE = (W−Wb + ΔW _H ) / (1−η) (1) ΔW _H : Width expansion η = f (W, H, RE, R, Tc) (2) where W: Width of entry side plate (mm) ), H: Inlet plate thickness (mm), RE: Edger roll diameter (mm), R
: Horizontal roll diameter (mm), Tc: Inlet temperature (° C)

In the edger automatic sheet width control, finish rolling is started by the set-up control, and the sheet width W measured from the time when the leading end of the material to be rolled reaches the sheet width detector on the exit side of the first stand. ₁ is compared with the target plate width Wa on the first stand exit side, and a plate width deviation ΔWa is calculated by equation (3). ΔWa = Wa−W ₁ (3) The correction amount ΔEa of the vertical edger is reduced by the equation (4) so that the deviation ΔWa approaches zero, and the width control by the vertical edger is performed. _{ΔEa = (ΔWa + ΔW H a} ) / (1-η) ... (4) However, ΔW _H a: width expansion of the first stand

The above-described automatic edger width control is a control based on the detection result of the width detector on the exit side of the first stand.
Return of dog bone width due to width reduction of vertical edger Δ
To correct the setup calculation error of W _M and broadening [Delta] W _H by the horizontal rolling, responsiveness is fast, can very small longitudinal direction of the plate width deviation of the rolled material, carrying out the plate width control precision that Can be.

The sheet width detector used in the present invention is not particularly limited as long as it can detect the sheet width of the material to be rolled.
For example, there are a lower light source system and an infrared system, both of which convert light passing through the rotating slit mechanism of the detecting unit into a pulse-like electric signal with a detector, and abruptly when the rotating slit passes through the brightness of the plate edge. The board width is detected from the change in the light quantity.
The temperature detector for detecting the surface temperature of the material to be rolled used in the present invention is not particularly limited as long as it can detect the surface temperature of the material to be rolled, and examples thereof include a radiation thermometer.

[0019]

【Example】

Embodiment 1 Hereinafter, a method of controlling a sheet width in hot continuous rolling according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a schematic general layout diagram for explaining a sheet width control method in hot continuous rolling according to the present invention, and FIG. 2 is a schematic system diagram of a rolling position calculation and a rolling correction amount calculation of a vertical edger on a finishing rolling mill group entrance side. Fig. (A) is a schematic diagram of the rolling position calculation of the vertical edger on the entrance side of the finishing mill group, and (b) is a schematic diagram of the reduction amount calculation of the vertical edger on the entering side of the finishing mill group. 3 is a graph showing an example of the relationship between the product plate width of the material to be rolled and the deviation between the target plate width and the product plate width at each position.

[0020] In Figure 1, the first stand 1 ₁ 1,
Second stand _1-2 ,... A group of finishing mills consisting of the n-th stand 1- _n , which is usually composed of 6 to 7 stands.
2 is a vertical edger installed on the entrance side of the finishing mill group 1,
3 plate width detector installed at the entry side of the finishing mill group 1, 4 is the plate width detector installed in the outlet side of the first stand 1 _1, 5 was placed on the exit side of the finishing mill group 1 It is a plate width detector. 6
Is a temperature detector for detecting the surface temperature of the material 7 to be roughly rolled by the rough rolling mill group installed on the entry side of the finishing mill group 1. Reference numeral 8 denotes a control unit for controlling the feedback plate width, to which the plate width detected by each of the plate width detectors 3 to 5 and the surface temperature of the material 7 to be rolled detected by the temperature detector 6 are inputted.
9 is a finish-rolled hot-rolled steel strip.

When the controller 8 receives the sheet width and the surface temperature of the material 7 to be rolled from the sheet width detector 3 and the temperature detector 6, the controller 8 stores the sheet width previously stored for each steel type and product size of the material 7 to be rolled. Based on the target plate width at the time of passing through the detectors 4 and 5,
Each stand 1 ₁ of the finishing mill group 1, 1 _2, ... _1-n rate of, for calculating a roll angle. Further, based on the target sheet width at the time of passing through the sheet width detectors 4 and 5 previously stored for each steel type and product size, the control unit 8 controls each of the sheet width detectors 4 and 5 as shown in FIG. Based on the difference between the target plate width at the time of passing and the product plate width, the target plate widths Wa and Wb at the time of passing through the respective plate width detectors 4 and 5 are calculated. Further, the control unit 8
As shown in FIG. 2A, the final target sheet width Wb and the material 7 to be rolled inputted from the sheet width detector 3 and the temperature detector 6
Finishing mill group 1 based on the sheet width W and the surface temperature Tc of
The edging amount ΔE of the vertical edger 2 on the entry side is calculated by the above equation (1). Then, the control unit 8, each stand 1 ₁ of the finishing mill group 1, 1 _2, and is configured to start rolling in the rolling schedule calculated to ... _1-n and the vertical edger 2.

Further, when the control unit 8, after starting the rolling at rolling schedule by the set-up control, the tip of the rolled material 7 has arrived at the first stand 1 ₁ of the delivery side of the strip width detector 4 From FIG. 2, as shown in FIG. 2B, the measured plate width W ₁ input from the plate width detector 4 and the target plate width W
The deviation ΔWa from the vertical edger 2 is calculated by the above equation (3), and the reduction amount ΔEa of the vertical position of the vertical edger 2 at which the deviation ΔWa becomes zero is calculated by the above equation (4). It is configured to correct. further,
Control unit 8, the hot rolled strip to a target strip width Wa, which is input from the plate width detector 5 of the finishing mill group 1 delivery side of a plate width detector 4 passes through the point of the first stand 1 ₁ Output side The edger automatic plate width control is performed by learning from the deviation ΔWb between the measured plate width W ₂ of No. 9 and the target plate width Wb at the time of passing through the plate width detector 5 and always calculating and correcting the optimum target plate width. ing.

With the above-described configuration, the control unit 8 controls the sheet width detector 3 and the temperature detection by the sheet width W and the surface temperature Tc of the material 7 to be rolled rough by a group of hot rough rolling mills (not shown). When input from the device 6, each of the sheet width detectors 3, 4, 5 determined in advance for each steel type and product size of the material 7 to be rolled.
The basis of the target plate width in the pass point, the stand 1 ₁ of the finishing mill group 1, 1 _2, ... _1-n rate of, for calculating a roll angle. Further, based on the target sheet width at the time of passing through the sheet width detectors 4 and 5 previously stored for each steel type and product size, the control unit 8 controls each of the sheet width detectors 4 and 5 as shown in FIG. Based on the difference between the target plate width at the time of passing and the product plate width, the target plate width Wa at the time of passing through each of the plate width detectors 4 and 5,
Calculate Wb. Further, as shown in FIG. 2A, the control unit 8 determines the final target sheet width Wb and the sheet width W and the surface temperature Tc of the material 7 to be rolled inputted from the sheet width detector 3 and the temperature detector 6. The edging amount ΔE of the vertical edger 2 on the entry side of the finishing mill group 1 is calculated by the above equation (1). Then, the control unit 8, finishing each stand 1 ₁ of the rolling mill group 1, 1 _2, ... to start rolling in rolling schedule by the calculated up controlled _1-n and vertical edger 2.

When the rolling is started, the control unit 8
As shown in (b), the measured strip width W ₁ which is input from the first stand 1 ₁ delivery side the target plate width Wa and the plate width detector 4
Is calculated by the above equation (3), and the amount of correction ΔEa of the vertical position of the vertical edger 2 at which the deviation ΔWa becomes zero is calculated by the above equation (4).
Is performed. Further, the control unit 8 controls the first
The target plate width Wa in the plate width detector 4 passes when the stand 1 ₁ delivery side, a plate width W ₂ of the hot rolled strip 9 which is input from the plate width detector 5 of the finishing mill group 1 delivery side Learning is performed from the deviation ΔWb of the target plate width Wb at the time of passing through the plate width detector 5, and the calculation is corrected so that the optimum target plate width is always obtained. Therefore, in the hot-rolled steel strip 9 that has been finish-rolled, the sheet width deviation is very small over the entire length excluding the tip, and the sheet width can be controlled with high accuracy.

Example 2 A thickness of 50 mm and a width of 1020 were roughly rolled by a rough rolling mill group.
mm bar using a finishing mill group consisting of 7 stands,
Finish rolling at a finish rolling speed of 600 m / min.
When producing a hot-rolled steel strip having a width of 0 mm and a width of 1000 mm, the vertical width of the entrance side of the finishing mill group is determined based on the deviation between the detection result of the width detector and the target product width. A conventional example in which the width reduction correction amount of the die edger is arithmetically controlled, and a finishing rolling mill group input based on a deviation between a target width and a detection result of a sheet width detector installed on the exit side of the first stand of the finishing rolling mill group. For each of the examples of the present invention in which the width reduction amount of the vertical edger on the side was arithmetically controlled, the finishing width deviation ΔW was obtained from the product target plate width and the actual product width, and the product yield was obtained. Table 1 shows the results.

[0026]

[Table 1]

As shown in Table 1, the width reduction of the vertical edger on the entrance side of the finishing mill group is corrected based on the deviation between the detection result of the sheet width detector installed on the exit side of the finishing mill group and the target sheet width. In the conventional example in which the amount is arithmetically controlled, the finish width deviation ΔW is 2.5
mm, based on the deviation between the target width and the detection result of the strip width detector installed on the exit side of the first stand of the finishing mill group, the width reduction of the vertical edger on the entrance side of the finishing mill group In the example of the present invention in which the correction amount is arithmetically controlled, the finishing width deviation ΔW is equal to 0.
The width is 8 mm, which enables a more accurate control of the width of the sheet than in the conventional example, and the product yield is improved by 0.17%.

[0028]

According to the present invention, the method for controlling the width of a strip in hot continuous rolling is based on a deviation between a target width and a detection result of a strip width detector installed on the exit side of a first stand of a finishing mill group. Since the width reduction correction amount of the vertical edger on the entrance side of the rolling mill group is arithmetically controlled, the response is fast, and the width is reduced on the entrance side of the finishing mill group, so that the sheet thickness is also sufficiently thick as 25 to 55 mm.
Since the width reduction amount can be increased, the width of the plate can be controlled with high accuracy, and the yield can be significantly improved by reducing the defective product quality and reducing the amount of side trimming.

[Brief description of the drawings]

FIG. 1 is a schematic overall layout diagram for explaining a sheet width control method in hot continuous rolling according to the present invention.

FIG. 2 is a schematic system diagram of a rolling position calculation and a reduction amount calculation of a vertical edger on the entrance side of a finishing mill group, and FIG. 2 (a) is a schematic system diagram of a rolling position calculation of a vertical edger on the entrance side of a finishing mill group. And (b) is a schematic system diagram of the calculation of the amount of reduction of the vertical edger on the entrance side of the finishing mill group.

FIG. 3 is a graph showing an example of a relationship between a product plate width of a material to be rolled and a deviation from a target plate width at each plate width detection position.

[Explanation of symbols]

1 finishing mill group 1 ₁ first stand 1 ₂ second stand 1 _n n-th stand 2 vertical edger 3,4,5 plate width detector 6 temperature detector 7 the rolled material 8 controller 9 hot rolled Steel strip

Claims (1)

[Claims] 1. A method for controlling a width of a finishing rolling equipment provided with a vertical edger on an input side of a group of continuous hot rolling mills comprising a plurality of rolling stand rows, the method comprising:
Measuring the sheet width of the material to be rolled between the stand and the second stand, calculating a deviation between the measured sheet width and a sheet width target value on the first stand exit side preset based on a rolling schedule, A width control method for hot continuous rolling, wherein a width reduction amount of a vertical edger is corrected based on a deviation.